1. Field of the Invention
The present invention relates to the field of displaying technology, and in particular to a light guide plate and a manufacturing method thereof.
2. The Related Arts
Liquid crystal displays (LCDs) have a variety of advantages, such as thin device body, low power consumption, and being free of radiation, and are thus of wide applications, such as mobile phones, personal digital assistants (PDAs), digital cameras, computer monitors, and notebook computer screens.
Most of the liquid crystal displays that are currently available in the market are backlighting liquid crystal displays, which comprise a backlight module and a liquid crystal panel mounted to the backlight module.
The principle of operation of the liquid crystal panel is that liquid crystal molecules are interposed between two parallel glass substrates and a plurality of tiny horizontal and vertical wires are arranged between the two glass substrates, wherein the liquid crystal molecules are controlled to change direction through an application of electricity so as to refract out light emitting from the backlight module to generate an image. Since the liquid crystal panel itself does not emit light, light must be provided from the backlight module in order to normally display an image. The backlight modules can be classified in two types, namely a side-edge backlight module and a direct backlight module, according to the site where light gets incident. The side-edge backlight module comprises an LED light bar, serving as a backlight source, which is arranged at an edge of a backplane to be located rearward of one side of the liquid crystal panel. The LED light bar emits light that enters a light guide plate (LGP) through a light incident surface at one side of the light guide plate and is projected out of a light exit surface of the light guide plate, after being reflected and diffused, to pass through an optic film assembly so as to form a planar light source for the liquid crystal panel.
As shown in FIG. 1, most of the medium- or small-sized light guide plates 100 use recessed or raised geometric grid dots 110 on a bottom thereof. Light from an LED light source 200 and transmitting through the light incident surface 410 into the light guide plate 100, before reaching the grid dots 110, is subjected to total reflection inside the light guide plate 100. Total reflection will be destructed for light reaching the grid dots 110 so that a portion of the light projects out from the light exit surface 430 that is formed on the upper surface of the light guide plate 100, as indicated by light a illustrated in FIG. 1. Another portion of the light is given off from the reflection surface 420 of the lower surface of the light guide plate 100, as indicated by light b of FIG. 1. The light b that emits from the lower surface of the light guide plate 100 is of no use. This leads to a waste of light, lowering down the light utilization of the light guide plate 100 and also increasing the cost of backlighting.